Assessing Water Level Variability in the Mekong Delta under the Impacts of Anthropogenic and Climatic Factors

In recent years, the water level in the Mekong Delta (MD) has undergone changes, attributed to the impacts of anthropogenic activities and climate change. Declining water levels have had implications for various aspects of life and aquatic ecosystems in the lower basin water bodies. Analyzing long-term trends in rainfall and water levels is crucial for enhancing our understanding. This study aims to examine the evolving patterns of water level and rainfall in the region. Data on water levels and rainfall from observation stations were gathered from the National Center for Hydrometeorological Forecasting, Vietnam, spanning from 2000 to 2014. The assessment of homogeneity and identification of trend changes were conducted using the Standard Normal Homogeneity Test (SNHT) and the Mann-Kendall test. The results indicate that changes in water levels at the Tan Chau and Chau Doc stations have been observed since 2010 due to the operation of flow-regulating structures in the upper Mekong River. Following the commencement of upstream dam operations, the water level at the headwater stations of the Mekong River has been higher than the long-term average during the dry season and lower than the average during the flood season. The study findings highlight the influence of altered rainfall patterns under the impact of climate variability (ICC) on water level trends in the study area. While rainfall plays a significant role in increasing water levels during the flood season, the operation of hydropower dams (UHDs) stands out as the primary factor driving water level reductions in the study area.